#include<stdio.h>
#include<string.h>
#define FIN "text.in"
#define FOUT "text.out"
#define Lmax 100000
char sep[]={" ,.;:0123456789!@#$?%^&*()-_`~..."},sir[Lmax],s[Lmax];
long sw,k,i,j;
int cuv=0,lit=0;
 int main(void)
{
 freopen(FIN,"r",stdin);
 freopen(FOUT,"w",stdout);
 gets(s);

 for( i=0;s[i]!=NULL;++i)
  {
   sw=0;
   if(s[i]==32)
   {
    sir[k++]=s[i];
    continue;
   }
   for(j=0;sep[j]!=NULL;++j)
    if(s[i]==sep[j])
     sw=1;
   if(sw==1)
    sir[k++]=' ';
   else
    sir[k++]=s[i];

  }
 for( i=0;sir[i]!=NULL;++i)
  {
   if(((sir[i]>='a') && (sir[i]<='z')) || ((sir[i]>='A') && (sir[i]<='Z')))
    lit++;
   if((sir[i]==' ') && (sir[i+1]!=' ') && (sir[i+1]!=NULL))
    cuv++;
  }
 printf("%d",lit/cuv);

 return 0;
}